36 
Pigmentation, Susceptibility and Race Selection 
population, the greater the excess of medium hair, and therefore the greater the 
excess of medium hair, the greater the death rate. This, however, is obviously not 
the sole factor, as it is found that the rate at which medium- haired children 
develop infectious disease is considerably greater than the average. 
(ii) Eye Colour. 
Table XXI shows that the effect of selection in the various eye colours follows 
closely that of the hair colours. The medium-eyed class by a very large margin is 
selected both for handicap by its large number of severe cases with subsequent 
disability and for extermination by its large number of deaths. The only excep- 
tion to this is in whooping cough where the light-eyed class suffer more severely. 
With the exception of the light-eyed class in diphtheria and whooping cough the 
other colours all suffer less by handicap or extermination than their proportion in 
the general population, and this happens at the expense of the medium-eyed class. 
TABLE XXI. Eye Colour. Showing the Percentages of the various Eye 
Colours in the General Population and in Hospital Patients, also 
the Percentages in each Colour of the total number of severe cases 
with recovery and of deaths. 
Dark 
Medium 
Light 
Blue 
Percentage in general population: 
Belvidere and Ruchill Areas . . . 
24-5 
34-0 
30-3 
11-2 
Scarlet Fever: 
Percentage in hospital patients 
Percentage of total severe cases with recovery 
Percentage of total deaths 
15- 0 
16- 8 
6-2 
62-0 
58-4 
65-7 
17- 8 
18- 7 
21-9 
5- 2 
6- 1 
6-2 
Diphtheria : 
Percentage in hospital patients 
Percentage of total severe cases with 
Percentage of total deaths 
recovery 
15-2 
121 
18-9 
44-4 
42- 9 
43- 2 
35-3 
40-9 
33-8 
5-1 
4-1 
4-1 
Whooping Cough: 
Percentage in hospital patients 
Percentage of total severe cases with 
Percentage of total deaths 
recovery 
15- 2 
17-2 
16- 7 
38-1 
38-0 
30-0 
35-8 
38-0 
46-7 
11-0 
6-9 
6-7 
Percentage in general population : 
Ruchill area only 
24-4 
32-4 
31-2 
12-0 
Measles, Ruchill only : 
Percentage in hospital patients 
Percentage of total severe cases with recovery 
Percentage of total deaths 
14- 5 
15- 9 
11-7 
60-2 
54-0 
58-4 
22-1 
25- 4 
26- 7 
3- 2 
4- 8 
3-3 
Next to the medium, the light-eyed class is selected for handicap and ex- 
termination, the dark-eyed less so, and the blue-eyed least of all. This order is 
maintained throughout with well marked degrees of diminution of adverse selection 
from the medium-eyed to the blue-eyed class. 
